An optical communication module is preferably small in size and low cost. In recent years, a VCSEL (vertical cavity surface emitting laser) has been examined as a light-emitting element used in an optical communication module. For convenience of the manufacturing process, a bare chip of the VCSEL generally has a configuration with a surface with a light-emitting portion and a back surface of the light-emitting portion where an anode and a cathode are provided, as shown in FIG. 1. In FIG. 1, reference numeral 1 denotes a cathode, reference numeral 2 denotes an anode, reference numeral 3 denotes a light-emitting portion, reference numeral 4 denotes a VCSEL, and reference numeral 5 denotes a bonding wire. In this illustration, for the anode 2, the entire back surface of the chip is a solid electrode. In addition, without being limited to this illustration, there is also a chip in which the anode 2 and the cathode 1 are opposite to those described above.
Accordingly, when manufacturing an optical communication module by mounting a light-emitting element, such as the VCSEL 4, on the printed circuit board with a known structure, light is emitted only in the direction perpendicular to the printed circuit board. In addition, the same is true for a light-receiving element; light is received only in the direction perpendicular to the printed circuit board.
In order to mount such a light-emitting element and a light-receiving element on the printed circuit board and to join the optical waveguide to them, methods such as the following (A) and (B) are used.
(A) Method of disposing an optical waveguide 11 vertically with respect to a printed circuit board 15 on which an IC 12 and a VCSEL 14 are mounted and joining it to a light-emitting portion 13 of the VCSEL 14, as shown in FIG. 2.
(B) Method of disposing an optical waveguide 21 horizontally with respect to a printed circuit board 25 on which an IC 22 and a VCSEL 24 are mounted, providing a mirror with an inclination of 45° and the like at the tip of the optical waveguide 21, and reflecting the light emitted from a light-emitting portion 23 of the VCSEL 24 by using the mirror so that the light is incident on the optical waveguide 21 and is coupled thereto, as shown in FIG. 3.
The known techniques regarding the present invention, for example, are disclosed in Patent Documents 1 to 4.
In recent years, optical wiring has been applied to high-speed communication apparatuses such as servers, optical wiring in automobiles, and small electronic apparatuses such as mobile phones. As efforts are being made to reduce the size and cost of such apparatuses, there is also a strong demand for miniaturization and low cost of optical transceivers. As light-emitting elements used for the optical transceiver, a laser diode (LD), a light-emitting diode (LED), and a vertical cavity surface emitting laser (VCSEL) are used. In addition, a photodiode is used as a light-receiving element. A fiber type or sheet type waveguide is used as the optical waveguide, and are made of silica glass, a polymer, or the like. For the structure and method of joining a light-emitting or receiving element to an optical waveguide in an optical transceiver, various methods have been examined (for example, refer to Patent Documents 5 to 8).
[Patent Document 1] Japanese Patent Application Laid-Open Publication No. 2004-309570
[Patent Document 2] Japanese Unexamined Patent Application, First Publication No. 2005-134600
[Patent Document 3] Japanese Unexamined Patent Application, First Publication No. 2004-253638
[Patent Document 4] Japanese Unexamined Patent Application, First Publication No. 2005-284248
[Patent Document 5] Japanese Unexamined Patent Application, First Publication No. 2006-11179
[Patent Document 6] Japanese Unexamined Patent Application, First Publication No. 2005-202025
[Patent Document 7] Japanese Patent Publication No. 3392748
[Patent Document 8] Japanese Unexamined Patent Application, First Publication No. 8-220368